Conformational analysis of cycloalkanes

  title={Conformational analysis of cycloalkanes},
  author={Veljko Dragojlovic},
Conformational analysis is a comparatively new area of organic chemistry that has been developed well after the theories of organic reactions, bonding in organic compounds and stereochemistry. It was only in the second half of twentieth century that its importance was fully recognized and its central role with respect to bonding, reactivity and stability of organic compounds was appreciated. Fundamental concepts of conformational analysis, a deeper discussion of the conformational analysis of… 

Seven Conformations of the Macrocycle Cyclododecanone Unveiled by Microwave Spectroscopy

This work has identified seven conformations of the macrocyclic ketone cyclododecanone using chirped-pulse Fourier transform microwave spectroscopy in combination with ab initio and density functional theory calculations to contribute to a better understanding of the intrinsic forces mediating structural choices in macrocycles.

Conformational Panorama of Cycloundecanone: A Rotational Spectroscopy Study

The conformational landscape of the medium-size cyclic ketone cycloundecanone has been investigated using chirped-pulse Fourier transform microwave spectroscopy and computational calculations. Nine

Dynamics and Entropy of Cyclohexane Rings Control pH-Responsive Reactivity

Activation entropy (ΔS‡) is not normally considered the main factor in determining the reactivity of unimolecular reactions. Here, we report that the intramolecular degradation of six-membered ring

Stability of Hierarchically Formed Titanium(IV) Tris(catecholate ester) Helicates with Cyclohexyl Substituents in DMSO.

A cyclohexyl substituent strongly prefers the chair conformation with large substituents in equatorial positions, while other cycloalkyls are structurally more flexible. In hierarchically formed

Unveiling the role of intra and interatomic interactions in the energetics of reaction schemes: a quantum chemical topology analysis.

The topological approach proposed in this contribution proves to be useful for the description of energy changes of apposite reaction schemes in chemically meaningful terms.

Recent Advances in the Total Synthesis of Natural Products Containing Eight-Membered Carbocycles (2009-2019).

This review illustrates the diversity and creativity in the elegant synthetic designs of eight-membered carbocycles in natural products with cyclooctane moieties and provides timely illumination and beneficial guidance for future synthetic efforts for organic chemists who are interested in this area.

Systematic description of molecular deformations with Cremer-Pople puckering and deformation coordinates utilizing analytic derivatives: Applied to cycloheptane, cyclooctane, and cyclo[18]carbon.

A new coordinate system based on the Cremer-Pople puckering and deformation coordinates is introduced to map the potential energy surfaces and reaction paths of cycloheptane, cyclooctane, and cyclo[18]carbon at the quantum chemical level and to determine for the first time all stationary points of these ring compounds in a systematic way.

Theoretical Studies of Structures and Conformational Analysis of Anthracene-2,7-diyl Cyclic Oligomers

The structures and conformation of anthracene-2,7-diyl cyclic oligomers were investigated by DFT calculations. The energy minimum and transition state structures of the oligomers ranging from penta...

The TACO Puzzle: A Phase-Transition Mystery Revisited

The organic salt (5-methyl-1-thia-5-azacyclo-octane-1-oxide) perchlorate (TACO) is known to undergo a single-crystal-to-single-crystal phase transition in the 276–298 K T range without a change in



Comprehensive conformational analysis of the four- to twelve-membered ring cycloalkanes: identification of the complete set of interconversion pathways on the MM2 potential energy hypersurface

Comprehensive conformational analysis of the 4- to 12-membered ring hydrocarbon series cyclobutane through cyclododecane has been carried out. The complete set of minima and saddle points has been

A Three-dimensional Energy Surface for the Conformational Inversion of Cyclohexane

While it is well known that chair forms of cyclohexane can interconvert without passing through the boat conformation, the same statement frequently comprises a source of confusion regarding the

Molecular dynamics study of the conformational properties of cyclohexadecane

Molecular dynamics has been used for the first time for the study of the conformational properties of cyclohexadecane, c‐C16H32. By analyzing a long molecular dynamics trajectory (14.5 ns) at 450 K,

Conformational Study of Cyclodecane and Substituted Cyclodecanes by Dynamic NMR Spectroscopy and Computational Methods

Low-temperature 13C NMR spectra of cyclodecane (1) showed the presence of a minor conformation, assigned to the twist-boat-chair-chair (TBCC), in addition to the expected boat-chair-boat (BCB). If

Conformations of large cycloalkanes: Cyclooctadecane, cyclononadecane and cycloicosane

A geometrical explanation is provided for the relative distributions of stable conformations in 16-, 18-, and 20-membered rings.

A Method for Drawing the Cyclohexane Ring and Its Substituents

The method consists of drawing two atom chains in the form of letters M and W. Next, the second atom of the one chain is connected to the second atom of the other chain and the fourth atom of the

Hyperconjugation not steric repulsion leads to the staggered structure of ethane

A series of ethane structure optimizations is reported, where successive removal of different interactions indicates that ethane's staggered conformation is the result of preferential stabilization through hyperconjugation.

Low‐mode conformational search elucidated: Application to C39H80 and flexible docking of 9‐deazaguanine inhibitors into PNP

It is demonstrated that for a conformational search involving cycloheptadecane, this rigorous implementation of mode following (c‐LMOD) is capable of finding all of the previously known structures, the first computational proof that mode following can be used for conformational searches conducted on a complex molecular system.